/**
 * 
 */

(function($) {
 $.fn.mailAutoComplete = function(options) {
  var defaults = {
   className: "emailist",
   email:  ["qq.com","sohu.com","sina.com","126.com","163.com","gmail.com","live.com","yahoo.com"], //邮件数组
   zIndex: 11 
  };
  // 最终参数
  var params = $.extend({}, defaults, options || {});
   
  // 是否现代浏览器
  var isModern = typeof window.screenX === "number", visibility = "visibility";
  // 键值与关键字
  var key = {
   "up": 38,
   "down": 40,
   "enter": 13,
   "esc": 27,
   "tab": 9 
  };
  // 组装HTML的方法
  var fnEmailList = function(input) {
   var htmlEmailList = '', arrValue = input.value.split("@"), arrEmailNew = [];
   $.each(params.email, function(index, email) {
    if (arrValue.length !== 2 || arrValue[1] === "" || email.indexOf(arrValue[1].toLowerCase()) === 0) {   
     arrEmailNew.push(email);      
    }
   }); 
   $.each(arrEmailNew, function(index, email) {
    htmlEmailList = htmlEmailList + '<li'+ (input.indexSelected===index? ' class="on"':'') +'>'+ arrValue[0] + "@" + email +'</li>'; 
   });  
   return htmlEmailList;   
  };
  // 显示还是隐藏
  var fnEmailVisible = function(ul, isIndexChange) {
   var value = $.trim(this.value), htmlList = '';
   if (value === "" || (htmlList = fnEmailList(this)) === "") {
    ul.css(visibility, "hidden"); 
   } else {
    isIndexChange && (this.indexSelected = -1);
    ul.css(visibility, "visible").html(htmlList);
   }
  };
   
  return $(this).each(function() {
   this.indexSelected = -1;
   // 列表容器创建
   var element = this;
   var eleUl = $('<ul></ul>').css({
    position: "absolute",
    marginTop: element.offsetHeight,
    minWidth: element.offsetWidth - 2,
    visibility: "hidden",
    zIndex: params.zIndex
   }).addClass(params.className).bind("click", function(e) {
    var target = e && e.target;
    if (target && target.tagName.toLowerCase() === "li") {
     $(element).val(target.innerHTML).trigger("input");
     $(this).css(visibility, "hidden");
     element.focus(); // add on 2013-11-20
    }    
   });   
   $(this).before(eleUl);
   // IE6的宽度
   if (!window.XMLHttpRequest) { eleUl.width(element.offsetWidth - 2); } 
    
   // 不同浏览器的不同事件
   isModern? $(this).bind("input", function() {
    fnEmailVisible.call(this, eleUl, true);
   }): element.attachEvent("onpropertychange", function(e) {    
    if (e.propertyName !== "value") return;
    fnEmailVisible.call(element, eleUl, true);  
   });
    
   $(document).bind({
    "click": function(e) {
     var target = e && e.target, htmlList = '';
     if (target == element && element.value && (htmlList = fnEmailList(element, params.email))) {
      eleUl.css(visibility, "visible").html(htmlList); 
     } else if (target != eleUl.get(0) && target.parentNode != eleUl.get(0)) {
      eleUl.css(visibility, "hidden");
     }
    },
    "keydown": function(e) {
     var eleLi = eleUl.find("li");
     if (eleUl.css(visibility) === "visible") {
      switch (e.keyCode) {
       case key.up: {
        element.indexSelected--;
        if (element.indexSelected < 0) {
         element.indexSelected = -1 + eleLi.length; 
        }
        e.preventDefault && e.preventDefault();
        break;
       }
       case key.down: {
        element.indexSelected++;
        if (element.indexSelected >= eleLi.length) {
         element.indexSelected = 0; 
        }
        e.preventDefault && e.preventDefault();
        break;
       }
       case key.enter: {  
        e.preventDefault();  
        eleLi.get(element.indexSelected) && $(element).val(eleLi.eq(element.indexSelected).html());
        eleUl.css("visibility", "hidden");
        break;
       }
       case key.tab: case key.esc: {
        eleUl.css("visibility", "hidden");
        break;
       }
      }
      if (element.indexSelected !== -1) {
       eleUl.html(fnEmailList(element));
      }
     }
    }
   });  
  });
 };
})(jQuery);